barTintColor

itemPositioning

Specifies tab bar item positioning. Available values are:

fill - distributes items across the entire width of the tab bar

center - centers item in the available tab bar space

auto (default) - distributes items dynamically according to the user interface idiom. In a horizontally compact environment (e.g. iPhone 5) this value defaults to fill, in a horizontally regular one (e.g. iPad) it defaults to center.